[RFC] Fix BFD leak in solib-darwin.c

[Tom Tromey]

>>>>> "John" == John Baldwin <jhb@FreeBSD.org> writes:

Re-replying...

John> Simon has noticed several instances of this bug where release()
John> was used instead of reset().

I wonder whether we ought to mark the release method as
"warn_unused_result" to try to avoid future bugs like this.  Another
idea is to try to reduce the number of calls to release generally, by
changing more things to take rvalue references or the like.

Tom